
# 简单的遍历列表，复杂度一般
def sequentialSearch(alist,item):
    pos = 0
    found = False
    while pos < len(alist) and not found:
        if alist[pos] == item:
            found = True
        else:
            pos = pos + 1
    return found

def orderedSequentialSearch(alist,item):
    pos = 0
    found = False
    stop = False
    while pos < len(alist) and not found and not stop:
        if alist[pos] == item:
            found = True
        else:
            if alist[pos] > item:
                stop = True
            else:
                pos = pos + 1
    return found


